Secular variations in the geomagnetic field in St. Petersburg and the adjacent area from historical data, 1630–1930

• Published in: Geomagnetism and Aeronomy 2013-09, Vol.53 (5), p.642-649
• Main Authors: Ptitsyna, N. G., Demina, I. M., Tyasto, M. I., Khrapov, B. A.
• Format: Article
• Language: English
• Subjects: Data analysis; Earth and Environmental Science; Earth Sciences; Geomagnetic field; Geophysics/Geodesy; History; Magnetic fields
• ISSN: 0016-7932; 1555-645X; 0016-7940
• DOI: 10.1134/S0016793213040117

Geomagnetic field parameters have been measured in different sites of the northwest of Russia for hundreds of years. This work presents the results of numerous measurements in St. Petersburg, as well as in the Gulf of Finland within the zone from 25° to 30°30′ E and from 59° to 61° N. The first measurements were made in the period1630–1650. For this work, archival data, provided by the Archives of the St. Petersburg Magnetic Observatory (SPbF IZMIRAN), and data from different historical records have been used. Data on the Earth’s magnetic field variations in St. Petersburg have been recorded since 1726; they were analyzed and corrected to get a uniform and complete data set. The reconstructed long-term data set of magnetic variation measurements in St. Petersburg was compared with the GUFM1 historical model. This model allows us to calculate the values of all parameters of the main magnetic field in any place on the Earth since 1590. The comparative analysis carried out by us has revealed a discrepancy between the model and measured values. This discrepancy can be caused by local secular variations in the magnetic field in the St. Petersburg region. The correction of the area-averaged secular variation makes this discrepancy insignificant.